What made Anders Breivik quote from the Daily Mail

So hysterical is the immigration debate thatMelanie Phillips and Jeremy Clarkson are cited in the killer's manifesto

The European far right has been at pains to distance itself from Anders Behring Breivik's psychotic act of holy war on Friday and present his actions as an isolated act of extremism by a lone madman.

But his ideas and motivations reflect a set of assumptions that spans the far right and many mainstream political figures and media commentators.

In his classic study of the American right, The Paranoid Style in American Politics, Richard Hofstadter once observed a tendency towards "heated exaggeration, suspiciousness, and conspiratorial fantasy" to which the American right was particularly prone.

In Hofstadter's formulation, "The paranoid spokesman sees the fate of conspiracy in apocalyptic terms — he traffics in the birth and death of whole worlds, whole political orders, whole systems of human values. He is always manning the barricades of civilization."

These characteristics have been evident for many years in Europe's shrill and often hysterical "debate" about immigration.

For more than a decade, internet bloggers, far-right demagogues and mainstream media pundits have depicted Muslim immigration as an ‘invasion' facilitated by a liberal/leftist political and cultural establishment driven by political correctness and a suicidal ‘ideology' of multiculturalism.

Few people are likely to be surprised that Breivik praised the English Defence League in his 1,500-page 'manifesto'. But he also quoted both Melanie Phillips of the Daily Mail (often and at length) and from Jeremy Clarkson's Sunday Times column.

He cites an article by Phillips (above right) about Labour's immigration policy in which she writes: "It was done to destroy for ever what it means to be culturally British and to put another 'multicultural' identity in its place." And he quotes Clarkson (above left) saying: "Discrediting national flags as signs of 'bigotry' is happening all over the Western world."

This depiction of 'indigenous' European cultures as an endangered species also extends to more intellectually respectable mainstream conservatives such as Niall Fergusson and Sir Martin Gilbert.

Both historians have praised the conspiracy theory/fantasy of Eurabia, propagated by the British/Egyptian writer Bat Ye'or, which argues that Europe is being inexorably transformed into a Muslim colony - a notion that has become a virtual idee fixe in the visions of cultural downfall propagated by the extreme right.

All these ideas can be found in Breivik's video, 2083: A Declaration of European Independence, which he posted on Youtube (now removed) to justify his actions on Friday.

Accompanied by a soundtrack of portentous music, a succession of images, texts and slogans presents a dark vision of a continent already subjugated by a "multi-culturalist alliance" of Marxists, "suicidal humanists", "capitalist globalists" and jihadists, in which "a majority of our cities will be Muslim cities" by 2025.

For Breivik, multiculturalism is "an anti-European hate ideology" propagated by the "Cultural Marxist traitors" who are paving the way for a Eurabian Europe.

Interestingly Breivik singles out the BBC as a particularly egregious component of this multicultural/jihadist conspiracy, with a mock mission statement that proclaims: "If you don't support our cultural Marxist views you are, by default, a fascist-racist-Nazi-monster".

This sense of victimhood is a recurring feature of what we might now call ‘the paranoid style in European politics', and it is not limited to right-wing internet forums and anti-Muslim hate sites.

Among the Melanie Phillips pieces Breivik cites in his manifesto is a recent one in which she argued that the BBC rather than Murdoch's News International was the real threat to British media because its world view was based on the idea that "traditional Christians are all fundamentalist bigots… opponents of mass immigration are racist".

The point about this analysis is that it is not an analysis at all. It is merely a set of prejudices without any empirical foundation. Breivik's formulations reflect the same tendencies. But where he differs from some – not all – of his contemporaries, is in his resolute determination to ‘act' in order to prevent the 'evil genocide' taking place in Europe.

Thus, on Breivik's video, potted vignettes of Charles Martel, El Cid, Richard the Lionheart and – unusually – Vlad the Impaler alternate with pictures of the Crusades as an inspiration for a new Knights Templar offensive aimed at 'decimating' the Cultural Marxists and driving Muslims from Europe.

This new knightly order is embodied by Breivik himself, the ideal of the 'Perfect Knight'. In the last section of the video, comic-book illustrations of sword-wielding knights cut to photographs of the steroid-taking comic-book crusader, posing for posterity as a Freemason in some kind of military uniform covered in medals, and action-man style in a wetsuit with a machine-gun.

Geert Wilders, Marine Le Pen and the EDL leadership may well be shocked at the horror which this homicidal narcissist unleashed in Oslo and on Utoeya island, but those who propagate fantasies of immigrant invasions and civilisational collapse cannot be entirely surprised that there are those who take such fantasies literally and engage in their own form of 'war'.

Breivik is not the first far-right activist to contemplate such acts in recent years, and unless European civil society and politicians can find the will to recognise, confront and isolate the toxic and often delirious bile in which his fantasies of 'resistance' marinated for so long, he may not be the last.

• Matthew Carr is the author of 'The Infernal Machine: an Alternative History of Terrorism', published by Hurst.